Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/3c31ce933f48
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #14912 from davidflanagan/bug939679

Bug 939679: compute the right camera preview size on HD devices r=dmarcos

========

https://hg.mozilla.org/integration/gaia-central/rev/f1092ff15f42
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Bug 939679: compute the right camera preview size on HD devices

========

https://hg.mozilla.org/integration/gaia-central/rev/84146f63920f
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #15051 from davidflanagan/bug939962

Bug 939962: set the willReadFrequently flag when creating the 2D context... r=snorp

========

https://hg.mozilla.org/integration/gaia-central/rev/4452a66717b2
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Bug 939962: set the willReadFrequently flag when creating the 2D context for saving an edited image